Aung San Suu Kyi promised Tuesday to use her party's popular mandate to drive Myanmar's peace process as she outlined a vision of a federal future to ethnic rebels who have battled for decades.

She was speaking at a fresh round of talks between the government, army and ethnic minority armed groups, at which crucial economic and social issues that spurred the violence will be discussed.

Those include the ownership of natural resources, seen as a major factor in conflicts that have displaced tens of thousands of people and cost countless lives.

Suu Kyi, whose party won the November general election, said she was optimistic the "fighting will be finished soon" if the nation's political standards are improved and all groups work together.

"We cannot build lasting peace without national reconciliation," she said.

"Now we are ready to lead the peace process, because we have the power invested in the mandate given to us by the people and ethnic minorities."

It was the first time the democracy champion had taken a leading role in years-long official peace efforts.

The painstaking negotiations have until now been steered by reformist President Thein Sein, who was also present at the talks in the national capital Naypyidaw.

However, deep challenges remain. Some major armed groups have shunned the talks altogether and clashes are continuing in parts of the country between rebels and soldiers.

Powerful army chief Min Aung Hlaing also spoke at the opening of the five-day talks, calling the meeting a "historic event" which could help bring "lasting peace, stability and security" for the country.

- Uneasy relationship -

Political dialogue is a central demand of the ethnic minority armies, who for generations have fought for greater autonomy in the mountainous and resource-rich borderlands.

Ahead of the election, analysts predicted Suu Kyi would struggle to win support among ethnic voters because of the Nobel laureate's majority ethnic Bamar heritage.

But her National League for Democracy swept to a thumping majority across the country including the frontier regions.

Suu Kyi told Tuesday's talks that "a real democratic federal nation" was possible if all ethnic groups cooperate in a spirit of "brotherhood and respect".

Observers say major stumbling blocks lie ahead, including fostering unity and negotiating the thorny issue of ownership of resources.

But the most critical challenge is seen as Suu Kyi's uneasy relationship with the nation's still hugely powerful military, which holds the key to securing a lasting peace.

The army in part justified its fifty-year stranglehold on Myanmar with fears that ethnic divisions would fracture the nation. It rejected out of hand the concept of federalism.

But federalism has gradually become a central concept in peace discussions instituted by Thein Sein's government, which replaced outright junta rule in 2011.

In October those efforts yielded a ceasefire with some rebel groups, although the agreement fell short of a binding nationwide truce.

The president said Tuesday's meeting marked the "beginning of a process to build a union based on democratic and federal principles".

The former junta general, who is trying to secure his peacemaking legacy, said the conference was being held "in order to hand over the peace process to the incoming government smoothly".

But several major ethnic armies, including in war-torn northern Kachin and Shan states, have refused to sign a national truce until all groups are brought into the deal -- notably smaller organisations locked in conflict with the military.

Tun Zaw, spokesman for the United Nationalities Federal Council which represents six armed groups, said his organisation was boycotting the talks because they lack "inclusively".